APFIVE Solving a Radical Equation with Summation
Solve for $$x$$ in the equation
$$\sum_{n=1}^{2} \frac{n*x}{n+1} = \sqrt{x+9}.$$
First, note that the summation simplifies to $$\frac{7*x}{6}$$.
| n | Expression \
|—|------------| \
| 1 | $$\frac{x}{2}$$ | \
| 2 | $$\frac{2*x}{3}$$ |
A
$$x=\frac{90*\sqrt{2}-18}{49}$$
B
$$x=\frac{18+90*\sqrt{2}}{49}$$
C
$$x=\frac{18-90*\sqrt{2}}{49}$$
D
$$x=\frac{90*\sqrt{2}+18}{7}$$
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